Excess-voltage-protecting device for electric lines.



T. A. r. HOLMGREN a K. A. Lmnsmiim. EXCESS VOLTAGE PROTECTING DEVICE FOR ELECTRIC LINES. APPLICATION FILED FEB- 17. 914.

1,236,563; Patnted Aug. 14,1917.

UNITED STATES PATENT OFFICE.

TORS'IEN FRITHIOFSSON HOLMGREN, F TROLLHKTTAN, AND KARL ARV ID LINDS'I'RfiM, 0F STOCKSUND, SWEDEN.

'nxcEss-voLrAcn-rno'rnctrmG :onvicn FOR ELECTRIC LINES.

for Electric Lines, of which the following is a specification.

A common ground for disturbances in the function of electric transmission lines consists',,as is well known, of the so-called excess-voltages, e. the rises of potential which may occur in said lines for several various reasons and-which cause disruptive or surface discharges over theinsulator's and thus spoil the latter. a

An excess voltage protecting device, the purpose of which is ,to prevent the formation of such excess voltage, must be-adapted for conducting oif rapidly enough the electric charge which may be considered as the direct cause of the rise of potential, and only in the degree as the protecting device is capable thereof, it will fulfil its purpose efliciently.

for this purpose which consists in a conducting wir'e mounted adjacent to- (above, beneath or at the side of) the wires or wire strands forming the electrical line proper.

This conducting wire shall have a good electrical connection to earth and consequently in this re pect it corresponds to the generally-known and rather frequently used ground-wire (or wire strand). According to the present invention, this ground wire shall be made with such a small diameter (21. e. such a small sectional area) that the sion line or wires and the ground wire. 1 By this means, the electrical charge corresponding; to the rise of potential is discharged or conducted away from the transmission line or wires whereby the Said rise is prevented.

The required dimensionsand position Specification of Letters Patent.

The present inventionrelates to a device I Patented Aug. 14., 191 '1.

Application filed February 17, 1914. Serial No. 819,175.

' the ground wire for the aforesaid,purpose being easy to calculate in a known'manner, the posltion and dimensions can be chosen 1n each case which are suitable for causing the ground'wire to react for the excess voltage, 'on one hand but on the other not tocause losses at the working voltage normal for the transmission line or wires. "Thus by the present invention a new technical effectv 1s obtained from the usual ground wire.

i still larger scale. Fig. 6 shows 1n the same way as Fig. 2 a line with several excess voltage protectlng wires. In the different figures the same parts are indicated by the same letters of reference.

In Figs. 1 and 2, a, b, c, are the three line wires, for instance of a three-phase system,

which in the exampleshown aret. .angularly arranged and hung on insulators depending .from projecting 'ortions' of a pole p. The

" rectly on the frame work of the iron poles when such aroused or in any other way connected to earth. This wire may, as shownin Fig. 1, besupported also by intermediary Instead of one ground wire two or more -may of course be used whereby the efiiciency poles 7, arranged between the poles p supporting the line ,wires. The dimensions and cross-section of the" wire (1 should be such that the electric field occurring around it in the case of an excess voltage will be sufli-' c1ent to produce a so-called corona e'fl'ect.

For this purpose, an edged cross section, as

shown in Figs. 4 and 5, may be suitable for the wire (Z, but a circular cross-section, as

shown in Fig. 3, may also be employed.

' According to Fig. 6 several protecting wires dare arranged connected .to the earth in any suitable manner.

Having now described our invention, we

- declare, that what we claim is 1. Method of protecting electric linesfrom excess voltage consisting in arranging a conducting member runn ng alongthe transmission line Wires proper, said conducting member being connected tithe earth in such a way that it have substantially the same potential as the earth electric lines comprising a conductor connected to the earth in such a way that it will have substantially the same potential as the earth and arranged along the said line conductors proper, and located in such a distance to the line conductors v proper and dimensioned in such a manner that adischarging efi'ect termed corona takes place on the surface of the earth connected conduct-or, when the potential of the line conductors proper rises above the normal working voltage.

3. Excess voltage protecting device for electric lines comprismg several conductors connected to the, earth in such a way that they will have substantially the same potential'as the earth, arranged alon the said line conductors proper and located in such a distance to the same and dimensioned in such a manner that a discharging effect termed corona takes place on the surfaces of the earth connected conductors, when the potential of the line conductors proper rises above the normal working volta e.

In witness whereof we have ereunto set our hands in presence of two witnesses.

TORSTEN ANDREAS FRITHIOFSSON HOLMGREN. KARL ARYID LINDSTBOM. -Witnesses: Glm'ra Pmx,

A'Uc, HoonmN. 

